Michinao Tan1, Daisuke Ueshima2, Kazushi Urasawa3, Naoki Hayakawa4, Yutaka Dannoura5, Takahito Itoh6, Amane Kozuki7, Yoshinori Shimooka8, Taichi Hayashi3, Yusuke Sato3. 1. Cardiovascular Center, Tokeidai Memorial Hospital, Sapporo, Japan. Electronic address: limbsalvage.mt@gmail.com. 2. Department of Cardiology, Kameda Medical Center, Chiba, Japan. 3. Cardiovascular Center, Tokeidai Memorial Hospital, Sapporo, Japan. 4. Department of Cardiology, Asahi General Hospital, Chiba, Japan. 5. Department of Cardiology, Sapporo City General Hospital, Sapporo, Japan. 6. Department of Cardiology, Oji General Hospital, Tomakomai, Japan. 7. Department of Cardiology, Osaka Saiseikai Nakatsu Hospital, Osaka, Japan. 8. Department of Cardiology, Megumino Hospital, Eniwa, Japan.
Abstract
OBJECTIVE: To develop a scoring system that can adequately predict a successful guidewire crossing (S-GC) of below-the-knee (BTK) chronic total occlusions (CTOs) in angiographic evaluation. METHODS: A retrospective, multicenter, nonrandomized study examined 448 consecutive BTK CTOs in 299 patients treated with endovascular therapy in seven Japanese medical centers from April 2012 to April 2020. The cohort was classified into two groups: an S-GC group and a failed guidewire crossing group. RESULTS: The final logistic regression model created by a backward stepwise multivariate logistic regression model included five variables: "No outflow of the target vessel," "CTO length ≥200 mm," "Reference vessel diameter <2.0 mm," "Calcification at the proximal entry point," and "Blunt type at entry point." Optimisms were adjusted using 1000 bootstrap samples with replacement and candidate's risk score models developed according to optimism-adjusted correlation coefficients of risk factors. Choosing the best model as the Japanese-BTK (J-BTK) CTO score by comparing the optimism-adjusted area under receiver-operating characteristic curves it was decided to assign one point to "Blunt type at the proximal entry point," one point to "Calcification at the proximal entry point," one point to "Reference vessel diameter <2.0 mm," one point to "CTO length ≥200 mm," and two points to "No outflow of the target vessel." This rule was then used to categorize BTK CTOs into four grades with varying probabilities of S-GC: grade A (J-BTK CTO score of 0 and 1), grade B (score of 2 and 3), grade C (score of 4 and 5), and grade D (score of 6). Rates of S-GC in each grade (grades A, B, C, and D) were 97.3%, 76.8%, 19.3%, and 0%, respectively. Lesions categorized as grade C or D have a lower chance of S-GC. Internal validation was performed using the Hosmer-Lemeshow test (P = .99). CONCLUSIONS: The J-BTK CTO score predicts the probability of an S-GC of BTK CTOs and stratifies the difficulty of endovascular therapy for BTK CTOs in angiographic evaluation.
OBJECTIVE: To develop a scoring system that can adequately predict a successful guidewire crossing (S-GC) of below-the-knee (BTK) chronic total occlusions (CTOs) in angiographic evaluation. METHODS: A retrospective, multicenter, nonrandomized study examined 448 consecutive BTK CTOs in 299 patients treated with endovascular therapy in seven Japanese medical centers from April 2012 to April 2020. The cohort was classified into two groups: an S-GC group and a failed guidewire crossing group. RESULTS: The final logistic regression model created by a backward stepwise multivariate logistic regression model included five variables: "No outflow of the target vessel," "CTO length ≥200 mm," "Reference vessel diameter <2.0 mm," "Calcification at the proximal entry point," and "Blunt type at entry point." Optimisms were adjusted using 1000 bootstrap samples with replacement and candidate's risk score models developed according to optimism-adjusted correlation coefficients of risk factors. Choosing the best model as the Japanese-BTK (J-BTK) CTO score by comparing the optimism-adjusted area under receiver-operating characteristic curves it was decided to assign one point to "Blunt type at the proximal entry point," one point to "Calcification at the proximal entry point," one point to "Reference vessel diameter <2.0 mm," one point to "CTO length ≥200 mm," and two points to "No outflow of the target vessel." This rule was then used to categorize BTK CTOs into four grades with varying probabilities of S-GC: grade A (J-BTK CTO score of 0 and 1), grade B (score of 2 and 3), grade C (score of 4 and 5), and grade D (score of 6). Rates of S-GC in each grade (grades A, B, C, and D) were 97.3%, 76.8%, 19.3%, and 0%, respectively. Lesions categorized as grade C or D have a lower chance of S-GC. Internal validation was performed using the Hosmer-Lemeshow test (P = .99). CONCLUSIONS: The J-BTK CTO score predicts the probability of an S-GC of BTK CTOs and stratifies the difficulty of endovascular therapy for BTK CTOs in angiographic evaluation.